1. Field of the Invention
The present invention relates to guidebar shogging linkage arrangements, and in particular, to a guidebar shogging linkage arrangement which permits the use of one shogging guide for a plurality of needle spacings and is capable of compensating for the arcuate movement of the shogging lever.
2. Discussion of the Relevant Art
Numerous shogging guide devices are known in the art. Some of these devices utilize a pair of slider bars connected to a changeover drive mechanism which selects either one slider bar or the other slider bar to determine the position of the shogging lever. Generally, these steerable elements are equipped with a return spring so that the spring energy must be overcome to set the desired displacement of the slider bar. One of these devices is disclosed in the German Offenlegungsschrift No. 2,056,325 dated May 25, 1972. Disclosed therein is a keying element formed as a roller which rolls on the steering surface provided at one end of both of the slider bars. The keying roller is affixed to the shogging lever and is pressed against the steering surface by a return spring attached to the guidebar. In order to alternate the keying roller with one or the other steering surface, the shogging lever may either be fixedly pivoted and the guide for the slider made movable upwardly or downwardly, or the lever itself may be mounted on an axis which is movable upwardly or downwardly. The shogging guide or steering arrangement includes multi-position cylinders having adjustable stops. A coupling linkage connects one end of the slider bar and is pressed against the adjustable stops by means of a return spring. In addition, ratchet teeth are provided which hook into a ratchet detent in the slider bar in order to alternately stop or release the slider bars for a new setting.
Utilizing a two-position shogging guide arrangement permits a much higher rate of speed to be accomplished for a given pattern selection and thus is vastly superior to shogging pattern drives which have only one guide arrangement. The double guide arrangement permits one slider bar to be adjusted to a new setting while the other slider bar is operatively connected to the guidebar for the displacement thereof. Unfortunately, however, there is a substantial mechanical loss which must be overcome because of the required locking arrangement needed for the slider bars and the fact that the driving force for the guiding arrangement requires overcoming the return force of the return springs which act upon the slider bars. Having to overcome the return springs introduces a limitation in the speed of operation and requires additional energy to overcome the spring forces.
Other types of shogging guide mechanisms have been utilized for warp knitting machines such as that disclosed in a textbook entitled, "Warp Knitting Technology" by D. F. Paling first published in 1952 and reprinted in 1970 by the Columbine Press (Publishers Limited). Another improved shogging or steering guide apparatus is disclosed in U.S. patent application Ser. No. 165,040, filed on July 1, 1980 and entitled "Guidebar Shogging Guide Apparatus for Warp Knitting Machines."
The present invention overcomes the shortcomings found in the prior art by utilizing a simplified guide apparatus which utilizes a pair of slider bars coupled to a keying element fixedly positioned on a shogging lever to control the displacement of the guidebar. The keying element's position is alternately selected from one or the other of the slider bars. The keying element may be positioned at different settings on the shogging lever thereby permitting the guidebar to be moved different incremental distances for the same incremental distance moved by the slider bar. A simple means for providing a changeover from the position of one slider bar to the other slider bar is disclosed. The instant apparatus does not operate against the forces of return springs and therefore is capable of much higher speeds of operation.